A medical device of this type is known, for example, from the patent specification U.S. Pat. No. 5,570,770.
Medical devices for medical diagnosis or therapy generally have an X-ray source and an X-ray detector, in each case in a housing. These two components are arranged at a distance from one another, wherein a patient to be examined or treated is positioned between the X-ray source and the X-ray detector. The X-ray source and the X-ray detector are positioned relative to the patient's body in such a way that an image of the desired cross section of the body interior may be captured. The alignment and positioning of the medical device may usually be performed with the aid of a motor drive.
Such devices are often equipped with a C-arm (i.e., an arched holder which may be rotated about a plurality of planes with the aid of a rail system). During use of the medical device, it is important that a moving part, for example the X-ray detector, comes close to the object to be examined in order to achieve the desired image quality. The X-ray detector has a comparatively large front face for receiving the X-rays and any desired point on this front face or over its circumference could come into contact with the patient to be examined. Such a collision may take place in any movement direction of the X-ray detector. This is undesirable and therefore a device of this type is equipped with a detection apparatus for identifying the collision with an object.
If contact between the moving part of the device and the object is identified, the movement of said device may be stopped in order to thus minimize the severity of the consequences of a collision. The cited patent specification of U.S. Pat. No. 5,570,770 describes a medical X-ray device that is equipped with an electrical detection apparatus for identifying collisions. Sensors in the device are designed to measure the current consumed by the drive motor or the power consumed thereby. These variables give an indication of the instantaneous force exerted on the moving part. This instantaneous value may be compared with an expected value for this force. If the difference between the instantaneous value and the expected value exceeds a predetermined threshold value, it is assumed that the movement of the moving part is impeded by an object and therefore a collision is taking place. Accordingly, an alarm signal is generated, and the movement is stopped.
Also known are housing claddings of moveable medical devices or parts of claddings in which a collision with an object acts on an electrical switch or on electrically switchable contacts. Such housing claddings are mounted in a sprung manner, for example, wherein a shift in the position of said housing claddings as a result of a collision is identified. Furthermore, there are solutions with elastic materials which actuate the electrical switch in the event of a predeterminable flexibility. The switching signals thus obtained are used to switch off a movement of the medical device.